It has long been a feature of cosmetic compositions that they comprise a fragrance. The addition of a fragrance can mask unpleasant odours or can improve consumer acceptance of a composition through delivering a pleasant smell. Indeed, the sole purpose of some compositions is the application of a pleasant odour to the skin, hair or other suitable substrate. However, for the most part, the fragrant effect of these compositions is transitory and the fragrance quickly becomes imperceptible.
Attempts have been made to improve the longevity of the fragrance. For instance, the fragrance may be formulated in such a way as to include a higher proportion of fragrance materials with a low volatility. This means the fragrance persists for longer. However, using less volatile materials restricts the fragrance characters that can be achieved. It has also been suggested that it may be possible to utilise cyclic oligosaccharides and in particular cyclodextrins. For example, JP-A-50/63126 discloses perfume and cyclodextrin complexes for use in bath preparations and JP-A-7/241333 discloses a long-lasting, room deodorising composition containing a fragrance and cyclodextrin.
One drawback of using cyclic oligosaccharides is that they are only sparingly soluble in commonly used solvents. Attempts have been made to increase the solubility of cyclic oligosaccharides by introducing various substituents. See, for example, JP-A-6/287127, JP-A-8/176587, JP-A-10/120,541, JP-A-62/161720 and JP-A-63/192706 all of which disclose compositions comprising perfume and substituted cyclodextrins.
Surprisingly, it has been found that compositions comprising fragrance and cyclic oligosaccharides having one or more unsubstituted alkyl substituents, wherein the weight ratio of fragrance to cyclic oligosaccharide is at least about 1:1, provide an initial burst of fragrance and improved fragrance longevity.
While not wishing to be bound by theory, it is believed that the fragrance material complexes with cyclic oligosaccharide of the present invention. It is believed that the stability profile of the complexes formed between the fragrance and the cyclic oligosaccharides of the present invention is such that a perceptible amount of fragrance is released over a sufficiently long time to satisfy the consumers desire for long lasting fragrance. In addition, it is believed that the weight ratio of fragrance to cyclic oligosaccharides in the present invention ensures that there is a ‘burst’ of fragrance on application of the composition to a suitable substrate.